1. Technical Field
The disclosure generally relates to a print head unit, particularly, to a print head unit and a method for manufacturing a patterned layer on a substrate with the print head unit.
2. Discussion of Related Art
Popularly used procedures for manufacturing a color filter include a pigment-dispersal method and an ink-jet method.
The pigment-dispersal method, widely used, utilizes color pigment photoresists forming red, green and blue sub-pixels by means of a spin-exposure-development. Specifically, red pigment photoresist, blue pigment photoresist and green pigment photoresist are sequentially applied to a glass substrate with a black matrix, exposed to the ultraviolet-light with the help of a photomask after drying, and developed to form red sub-pixel, green sub-pixel, and blue sub-pixel color layers respectively. Since the process is repeated three or more times, these manufacturing devices are both expensive to use and time-consuming to operate.
The ink-jet method uses an ink-jet device with at least one print head for depositing ink into a predetermined position on a substrate structure. A patterned layer is formed after solidifying the ink. Generally, for areas of the substrate structure exceeding a covering area of the print head, the print head of the ink jet device moves relatively in a matrix manner with the substrate to finish depositing the ink on the substrate.
The ink jet method is different from the pigment-dispersal method. In the ink jet method, each of R, G, and B ink is sprayed onto a substrate from respective nozzles of print heads to form a color layer. When the ink jet method is employed, the required amount of ink can be applied onto a required location at a specific time. Accordingly, almost no ink is wasted. Furthermore, since the sub-cells of R, G, and B can be formed simultaneously, the coloring time is reduced, and it is possible to conserve considerable cost.
Since the pitches between the nozzles of the conventional print head do not vary, they may not correspond to those of the corresponding cells in the color filter. In order to coordinate the two, it is necessary to rotate the print head about an axis perpendicular to the substrate, such that the projection of the nozzle on the substrate perpendicular to the printing direction is as the same as that of the cells in the same direction.
What is needed, therefore, is a print head unit to hold and adjust the print heads in multi degree-of-freedoms independently such that the pitches of the nozzles conform to those of the cells.